Question

if an AP, if the common difference (d) =-4, and the seventh term (a7) is 4, then find the first term

Answer 1

Hello dear,

SOLUTION ―
______________________________

let the First term be a and common difference is d .

Given in question
d = -4

the seventh term in A.P is 4 .

T 7 = 4

=> a + ( n - 1 ) d = 4

=> a + ( 7 - 1 ) × -4 = 4

=> a + 6 × (-4 ) =4

=> a - 24 = 4

=> a = 4 + 24

=> a = 28

so , first term is 28 .

_______________________________

Hope it's helps you.
☺☺☺

Answer 2

Hey friend, Harish here.

Here is your​ answer:

Given that :

• Common difference = -4

• Seventh term of AP = 4

To find :

The first term of the AP.

Solution:

We know that:

$a_n = a + (n - 1)d \\ \\ a_{7} = a + (7 - 1)d \: \\ \\ 4 = a - 24 \\ \\ a = 28$

Therefore First term of the AP is 28.
____________________________________

Hope my answer is helpful to you.